1. Field of the Invention
The present invention relates to a plasma display panel manufacturing method and a heat treatment apparatus.
2. Description of the Related Art
First, the structure of a common plasma display panel (referred to below as a PDP) will be described below as an example of a plasma display panel. FIG. 1 is an exploded perspective diagram showing the internal structure of the PDP, and FIG. 2 is a plan diagram schematically showing the structure of row electrode pairs 2 (X, Y) of the PDP.
In FIG. 1, plural row electrode pairs 2 (X, Y), a dielectric layer 3 that covers the row electrode pairs 2 (X, Y) and a protective layer 4 including MgO that covers the dielectric layer 3 are successively formed on an inner surface of a front panel 1 that serves as a display surface. Each row electrode pair 2 includes a transparent electrode 2a, which has a wide transparent conductive film such as ITO, and a metal electrode (bus electrode) 2b, which has a narrow metal film that supplements the conductivity of the transparent electrode 2a. 
On the other hand, partition walls 9 and phosphor layers 7R, 7G, and 7B of the three primary colors are formed on a back-side back glass panel 5, which is disposed so as to face the front panel 1 via the discharge space 8. The partition walls 9 are aligned in a direction orthogonal to the row electrode pairs 2 (X, Y), are disposed in bands between column electrodes 6 to form a display cell at each intersection portion, and partition a discharge space 8. The phosphor layers 7R, 7G and 7B of the three primary colors are disposed so as to cover the column electrodes 6 and side surfaces of the partition walls 9 with respect to the discharge space 8. A noble gas is charged and sealed inside the discharge space 8.
As shown in FIG. 2, the row electrode pairs 2 (X, Y) are alternatingly aligned column-wise so as to correspond to one line L of a matrix display and be adjacent at each line L with a discharge gap G sandwiched therebetween. At each line L, a display cell (discharge cell) is demarcated into unit light-emitting regions E by the row electrode pairs 2 (X, Y).
Next, the display operation of the display in the above PDP will be described.
First, ON cells (cells in which a wall charge is formed) and OFF cells (cells in which a wall charge is not formed) are selected by an address operation resulting from selective discharge between the column electrodes 6 and the row electrode pairs 2 (X, Y) shown in FIG. 2. After the address operation, a discharge sustain pulse is applied, with respect to the row electrode pairs X and Y, at once to all of the lines L, whereby surface discharge arises in the ON cells each time the discharge sustain pulse is applied. The phosphor layers 7R, 7G and 7B are excited by ultraviolet light generated by this surface discharge and caused to emit visible light.
[Patent Document 1]
JP-A-11-149873 (p. 2, FIGS. 7 and 8)
In the process of manufacturing a PDP such as the one described above, a heat treatment step is included in part of a formation step of a structure such as the electrodes, the partition walls, the phosphor layers, the dielectric layer and a black stripe layer. For instance, in the formation step of the dielectric layer, a glass paste including a mixture of glass powder, resin and a solvent is coated on a substrate, and the coated substrate is heat treated using a heat treatment apparatus such as a kiln.
A method of discharging exhaust gas of the heat treatment apparatus used in the heat treatment step will be described using the schematic diagram of FIG. 3, which shows a heat treatment apparatus.
As shown in FIG. 3, plural (three) exhaust pipes 111 are disposed at an upper portion of a heat treatment apparatus 110, and exhaust gas 112 generated from the inside of the heat treatment apparatus 110 is discharged from each exhaust pipe 111 to the outside (the atmosphere) of the heat treatment apparatus 110.
Thus, in the heat treatment step during the manufacture of the PDP, although resin components and solvent components are vaporized and removed at the time of the heat treatment, they are included as impurities in the exhaust gas 112 of the heat treatment apparatus 110. There is the potential for them to be diffused to the outside (the atmosphere) when they are discharged from the exhaust pipes 111.